Container



Jan. 19, 1,943. C. E. MCMANUS 2,308,530

CONTAINER Filed Oct. 29, 1942 Patented Jan. 19, 1943 UNITED STATESPATENT GFFICE CONTAINER Charles E. McManus, Spring Lake, N. J., assignorto Crown Cork & Seal Company, Inc., Baltimore, Md., a corporation of NewYork i Y vApplication october 29, 1942, serial No. 463,857 is claims.(ci. 22o-s4) This invention relates to containers and closurestherefor,as wellas materials for association with such closures,'e. g., spot oroverall facings.

The invention includes a novel container such as one of the metal cantype having its in-terior wall provided with a nlm containing polyvinylacetal resin. This resin lm is tough, strongly adherent to metal, isacid and alkali resistant, is particularly resistant to Water andmoisture In connection with the use of the polyvinyl acetal resincoating for packaging purposes, a Anoe table property is its ability towithstand'pasteurizing and sterilizing temperatures as distinguishedfrom usual thermoplastic materials, i. e., the coa-t-Y ings 'of thepresent invention do not soften objectionably at temperatures up tosubstantially 125 C.

In addition to the value'of the polyvinyl acetal vapor, and can beprepared to be resistant to resin as the principal or single nlm formingconmany common solvents. Suchacontainer is usestituent of the coating,it exhibits remarkable flll for Chemicals, pharmaceuticals, oils. andnllproperties when used in connection with-'other merolls otherproducts, but is markedly satisfilm forming materials, particularlychlorinated factoryinconnection with food products and bevrubber andalkyd resins, in the vletter ease in.. etages, including carbonatedbeverages, such as creasing the alkali resistance of the same.' beer,toward winch it is physically and chemically I have found that a Smallpercentage of polyinert- Moreover, a can liner ll'n Of polyvinyl ace-.vinylacetal resin in a coating solution of chlotal resinisbothtasteless and odorless. rinatod rubber win substantiauy.increase-the The various properties above set forth make toughness andexibility of the resultant ilm. and the coating equally useful as anexterior gor outadds materially ,to its life anditsneld of ap.

side lm for containers, and, in such cases, the lm can be suitablypigmented if desired or may be'clea-r and applied over a suitable basecoating, such as one containing aluminum, to give an attractiveappearance.

The properties above described make the polyvinyl acetalresixi coatingparticularly useful in connection with the interior and exterior coatingof caps and other closures, namely, crown caps, screw caps, lug caps.and pressed on caps. In this connection, the lm strength and adherenceof the coatings is so pronounced that a flat sheet of metal coated onone or both sides with a composition of polyvinyl acetal resin alone lorin combination with other suitable resins, may be punched. stamped, orotherwise acted upon to produce closures having a strongly adherentcontinuous protective nlm.

plication.

Conversely, I have found that the thickness of the film deposited from asolution of polyvinyl acetal resin can be increased withoutobjectionably raising thev viscosity of the solution by includingtherein an appropriate amount of a low viscosity grade ofchlorinated-rubber. Such a solution will deposit a thicker nlm than isobtainable with solutions of polyvinyl acetal resin alone havingsubstantially the same viscosity. Moreover, polyvinyl acetal solutionswhich are prepared for spraying, may, if desired, be rendered Ausefulfor roller coating in this manner.

The polyvinyl acetal resin also forms a highly resistant coating withlong oil alkyd resins. Such compositions while they may be used forlining and spotting purposes are also suitable for out- 'rh o1 1 aoetairesin nim is also usofui Side Coatings, 111 that they may bes111tab1y`p1efor mig niteor of closures having a `ausm-(m 40 mented toimpart a desired attract1ve color, I n nner, in that it is adherent' tosuon cushion iinor' this Connection Spotting Paper met' be preparedmaterial as composition cork, as well as cellulose b? cffatmg .theuntreated paper Wilth. Compos? products, such as paper, papeblikebodies, Genntion including polyvinyl acetal resin and longoil loseesters and Cellophane, and likewise is ad; alkyd resin, and thenapplying over this coating herent to metal. Thus, a continuous nlm maybe a thin lm 0f the polyvinyl acetal resin, or a lm provided as byspraying on the interior of the 0f Chlorlnated rubber and polyvlnylacetal resin. cap which will cover the raw edge, the exposed CoatingCompositions Including polyvinyl acearea of the skirt, and the exposedarea of the tal resin in accordance with this invention may cushionliner. In lieu of such construction, pabe applied directly t0 theinterior or exterior. per or metal fon may be Coated with a nlm of orboth of a metal container or closure, as well the polyvinyl acetal resinand punched out to as Cellulosic products, o r they may be applied formeither center spots or overall facings for upon a s llltable baseCoating. In this connection, the closure which are adnesiveiy bonded toor, the coatings may be transparent or suitably co1'- in some cases,loosely associated with the cushion cred, and in the case of transparentcoatings imliner or cap. :55 parta very attractwe appearance whenapplied for instance over a lustrous metal surface, such as one preparedThe coating may comprise compositions in which the polyvinyl resin isthe sole or main film forming' constituent, or, as stated, this resinmay be combined with other resins to produce films of variouscharacters. In each case, it is observed that either the strength,flexibility or resistance'A of the iilms are enhanced and productssuitable for a wide range of use made available.

Container bodies and can ends having seaming anges coated withcompositions containing sole-- 1y or mainly polyvinyl acetal resins orwith compositions including the same and other ingredients, such aschlorinated rubber, are very adequately sealed when a bottom is seamedto a container body, since such coatings are sufiiciently' flexible andplastic to accomplish this result under the pressure incident to rollingthe seam, This remarkable characteristicis observable inA the-.casezofcontainers having seamless bodies', i. e., containers which are drawnfrom a single' blank of metal as setiorth in application Serial-No.334,876. With such containers, when the interior is lined, the seamingilange is also coated with the lining and provides a satisfactory sealwhen the bottom is attached as by roll seeming. The coating, of course,will beof asuitable thickness, and not onlyisV the iange coated, butthebottom also. usually'will, although it is not always necessary, haveits sealing ange portion similarly coated,. as well as its vinteriorexposed bottom wall. It follows, of course, that instead of coating theflange of the body, the sealingflangeof the bottom may be coated with asealingiilm aloneor mainly of polyvinyl4 acetal resin; or chlorinatedVrubber and polyvinyl acetal resin.. This sealing characteristic. is alsouseful in connection with lock seam side seam cans for sealing the sideseams as well as the seams uniting the bottom and top or ends.

The polyvinyl acetal resins are soluble in a wide range of solvents, arecompatible with other resins, yand the coating solutions may bepigmented. The combination of these properties in one material hasenabled the compounding and formulation of coatings valuable in thecontainer and closure iield. as will be later exemplified. It isimportant to pointout that the properties of one polyvinyl acetal resinmay diier somewhat from those of another. For example, the resinmanufactured from formaldehyde (Formvar) is soluble in ethylenedichloride and insoluble in alcohol, while the resin made withbutyraldehyde (Butvar) is only moderately soluble in ethylenedichloride, but completely soluble in alcohol. The properties of theparticular andvarious polyvinyl. acetal resins. make the. resin widelyap,- plicable to meet a range of conditions, such as are encountered, inthe packaging field.

For example, a suitable spray coating preferably for lining cans andwhich is applied either to the black iron or to a coated base, such asaluminum on black iron, is prepared as follows: Example 1 GramsTrichloroethylene 350 Formvar resin /95 30 Diamyl phthalate '7 Wax 1Cans lined with this lacquer are baked in dry. circulating'hot air atabout 250' F, for about 30 minutes, and the' coating is stronglyadherent to the metal, tough, flexible. free of odor and taste, andresistant to acidsalkalies, water and moisture vapor. The lining isexcellent for such a difflcultly packageable product as beer. The lmstrength and stability persisted at high temperatures, e. g.,pasteurizing and sterilizing temperatures, and the film neitherpresented objectionable thermoplasticity at normal room temperatures,nor exhibited tackiness in storage. The plasticizer, such asdiamylphthalate is included to lower the softening point and to increasenexibility, but may be omitted in some cases. Also, the lm is renderedsufficiently plastic under pressure so that informing a can seam as byrolling the anges, the lm provides an excellent seam seal.,

This coating may be applied to paper which has been previouslyvarnished, or directly to metal foil, e. g., aluminum foil for capspotting or other facing purposes. In this connection, instead ofusing'Formvar resin, Butvar resin may be employed with a suitablesolvent such as an alcohol to produce a coating satisfactory for certainlining purposes in connection with cans and closures, although thisresin is not as desirable as Formvar where taste is easily aiected. Suchcoating is'also satisfactory for-producing paper spotting or facingmaterials by applying the same upon a previous coat of lacquer orvarnish, or directly to the surfaceof a metal foil.

I have alsocdiscovered that a container-lined with the. abovecomposition will adhere a silver coating, e; g., one producedby'vaporizing' silver in a. vacuum and causing it tov deposit on thecoated wall of the can. Such a silver film is thin, having a thicknessof about five miilionths of an inch and is continuous.

As. an examplel of a; composition including chlorinated rubber andpolyvinyl acetal resin to impart greater lm strength to the chlorinatedrubber film, a spray coating is prepared as follows and applied directlyto black iron or aluminum coated black iron:

Example 2 Chlorinated rubber (low viscosity, 10 centi- This coating isdried at about 240 F. in hot dry circulating air for about thirtyminutes. Cans lined with this coating were packed with beer andsubjected to accelerated aging. No oil taste could be detected in thebeer after an accelerated aging period which was quite severe and whichamounted to substantially three months. Since beer is extremelysensitiveto resins, this test further proved that the polyvinyl acetal type oiresin is useful as a lining material for food and beverage containers.

Example 3 To Example 1 there may be added an appropriate amount of lowviscosity (10 centipoises) chlorinated rubber to increase lm thicknessof the deposited hlm. For example, as much as 30 grams of thischlorinated rubber or more may be added as required, and I havediscovered that the viscosity of the solution is not objectionablyraised while a thicker lm isv Vobtainable than with solutions mainly oralone of polyvinyl acetal resin having substantially the same viscosity.

'Ihe inclusion of the chlorinated rubber may be in such amount as torender the sprayable solution useful `for purposes of roll coating.

'Ihe coating is dried as recited in connection with Example 1 at about240 F.

The following composition is useful as a protective coating for caps, i.e., is sprayed upon the interior of a cap before or after a cushionliner has tinuous strong film covering. For example, a cork compositionliner and the adjacent interior exposed area of the skirt, including theraw edge thereof, may be coated as described in4 application Serial No.347,53

Example 4 .l

Y Ounces Formvar resin /95 15 Ethylene dichloride 200Diamyiphthalate--II 3 'I'his composition coats the hills and valleys ofthe skirt of a crown cap, being applied to the usual lacquered surfacethereof, so that it completely covers not only the the raw edge thereofwith a continuous film. Instead of spraying to accomplish thisoperation, assembled crowns are held by a magnet and dipped into thecoating, so that the cushion'liner and skirt are covered. After drying,a continuous lm covered the liner and crown skirt on th interiorthereof, including the raw edge, and under test gave no olf taste tobeer or distilled water. Preferably, this coating isapplied by spraying,and while I have indicated that it is desirable as an interlor'lm tocover the cork composition liner and the adjacent interior of the skirt,including the raw edge, the entire exterior 'of the crown cap or otherclosure, vas well as the entire interior surface thereof may besimilarly coated. The coating is preferably dried at room temperature inabout thirty minutes by means of an air current created from a fan.

This coating is also useful for spot and overall facings of paper orfoil.

As heretofore explained, polyvinyl acetal resins are compatible withcertain long oil alkyd resins and may be used with these resins toincrease the alkali-resistance thereof. Coatings o1' this type aresuitable for varnishing the .outside of containers and closures, but maybe usedin many cases for interior lining purposes. Such compositions maycontain aluminum powder and give a bright leafed aluminum finish, or anyother suitable pigment may be added such as Titanox In this connectionalso, a clear solution may be made and applied over a suitable basecoating which may be of the Varnish or lacquer type or of a metal, suchas aluminum, and give a very attracive appearance.

The following is an example of a coating of this character:

Example 5 Parts Long oil alkyd resin (807 Resyl) 100 Polyvinyl acetalresin (Butvar) l- Wax (ceresin) 1 Chloroform 400 Butanol 350 'I'he abovecomposition is dried at about 280 F. in substantially thirty minutes indry circulating air, and forms a smooth continuous coating.

In addition to its utility as a coating material for metal containersand closures,v the composition of Example 5 can be applied to paper andbeen assembled therein so as to form a concork composition, but' theinterior exposed wall of 'the skirt, as well as thereafter a coating.such as set -fo'rth in Example 1, or a coating as set forth in Example 3may be applied thereover. The coating of the paper takes place on oneside thereof, and on the other side a suitable thermoplastic or spottingadhesive coating is formed, so that the paper, when dried and coiled,may be used with the usual high speed automatic spotting machinery forapplying center spots to caps, as well as other facings, such as overallliners thereto.

In connection with Example 5, a composition in which the amount ofpolyvinyl acetal resin exceeds the amount of alkyd resin may be utilizedin some casesas where it is desired to have a strong'lm which isplasticized somewhat by the* presence of the alkyd resin. v

It is to be understood that the coating compositions exemplified hereinmay be applied directly to the black iron of the metal can, or may beapplied to suitable base coatings thereon, either interiorly orexteriorly of the container. This applies with equal effect to metalclosures, as well as can bottoms and tops. As pointed out, thecompositions are not only rmly adherent to metal and form strong, toughfilms, but are likewise adherent to non-metallic materials, of'whichpaper and cork composition and varnishes and lacquers are suitableexamples.

While I have indicated a preference for spray coating, it is to beunderstood that roll coating vmay be resorted to, and I have explainedhow found certain of the sprayable solutions may be rendered suitablefor this purpose.

In connection with the polyvinyl acetal resin employed, this is acompletely or partially reacted product and prepared substantially inaccordance with the patent to Morrison, No. 2,036,- 092, granted MarchFormvar 15/95, I havealso used Formvar 4/90 and Formvar 7/95.

Also,-`I""have referred to the use of chemical plasticizers in making upthe several examples, but, in some cases, I use a drying oilplasticizer, such as tung oil.

The compositions described have all been lsatisfactory for the interiorand exterior coating of containers', container Abottoms and tops, aswell as closures, and for coating foils and paper to provide spottingand other facing materials. It is to be understood, of course, that Vtheproportions given in the several examples are purely by way ofillustration and may be modified without departing from the invention.

In connection with the coating of closures, as well as bottoms and tops,these are frequently initially provided with a surface coating oflacquer on both the interior and exterior thereof, and while thecompositions herein described l may be applied directly to such articleswithout the use of such lacquers, my compositions are particularlyuseful when deposited as films upon the lacquers or upon Ithe coating,lsuch as tin 31, 1936. In addition to and` top,- where the, same. isused. Inthe case-of closures. I ,have already explained that the closuremay, have itsv entire inner surface coated witha continuous film or `thecushion liner and` exposed inner surface of the skirt and raw edge maybe coated with a continuous nlm. The coatings where they are appliedexteriorly, are likewise continuous and coextensive with the containerbodies, bottoms and tops, and closures.

Thel sealing characterisic' of the compositions is an important featureof the invention, and, as pointed out, the composition may be coatedupon either the body seaming flange or the bottom seaming flange orboth, In this connection, in the case of cans of the side seam type, theseaminganges, either one or both of them, may be coated, with thecomposition and likewise the bottom and top may be sealed by coatingeither the body: flange or the bottom and top seaming flanges or both.Also, where the can bodies are lined with the compositions hereindescribed, the iiange coatings are co-extensive and continuous with thewall coating, and this is likewise true in the case of side seam iiangesand the seaming flanges of bottoms and tops.

With respect to be utilized, I employ a coating such as described inSerial No. 322,238, in the form of an aluminum varnish, or aluminum maybe included in the composition of Example to provide a suitable basecoating. Other base coatings may be lacquers and varnishes and enamelswhich are now commercially available. Also, the base coating may be ofpure metallic type, such as aluminum, tin, or alloys,

In connection withI the use of a base coating, the compositionsdescribed in the above examples are suitable for this purpose, in thatthey may be applied to paper, metal, etc., in as many coats as necessaryso as to build up a required base coat, and then the same composition oranother composition as described in the examples may be applied uponsuch base coat. This procedure is not preferred, but has been ernployedwith success. Q

It will be noted that Example 1 provides a coating or lining for metalcans comprising polyvinyl acetal resin and wax, while Examples 2 and 3provide films of chlorinated rubber, polyvinyl acetal resin and wax,Example 4 provides polyvinyl acetal resin only, and Example 5 provides afilm of a mixture of resins, including polyvinyl acetal resin and wax.In connection with Example 5,a part of the polyvinyl acetal resin may bereplaced by chlorinatedv rubber. if desired. in order to improve thealkali resistance of coating. In such a case, the total resin willl beat least 50%, and, as heretofore explained, the polyvinyl acetal resinalone is satisfactory forthe purpose, but there are cases where theinclusion of chlorinated rubber may be desirable.

As heretofore explained, the linings or coatthe base coating which mayasomo las ings produced by the present invention-are stable and have along life. Such linings are free of peeling or cracking, and do notsoften or melt above the pasteurization temperature of substantially 150F. In fact, the linings or coatings are stable at sterilizingtemperatures of 180 F. or higher.

It will be noted in the case of Examples 1 and 2 that the wax employedis less than 50% and that in the case of Example 3, as well as Example5, the resin is present in an amount of at least 50%.

It has-,been; found, that the presence,y of the rubber in certain ofthey compositions renders the wax and resin more compatible and enhances4their-miscibility particularlywhen resins such as polyvinyl acetalresins andalkyd resins are used.

While compositions containing polyvinyl resins are preferred, fortreatment of the containers and container parts, as described herein,other resin bases may be used such as urea aldehyde resin, cumar resinand arochlor resin, and mixtures thereof including the acetal resin.Also wax may-comprise the base with or without resinand among the waxeswhich may be employed are parailln, ozokerite, petroleum wax.hydrogenated vegetable oil wax, montan wax, halo-wax, candelilla,mineral beeswax, ceresin, carnauba and mixtures thereof. In the resin,wax or resin-wax base, there is in some cases included rubber and inaddition to chlorinated rubber, the rubber'may be provided by latex, alatex solution, with or without casein, a latexwax as-described in thepatent to Weiss, No. 1,563,410, December l, 1935, latex as described inthe patent to Schloz, No. 1,729,522, September 24,1929, and such rubberproducts as Vultex," fRevertex and other preparations containing rubber.

In some cases, the wax is present in the base as a mixture of acharacteristically hard high melting point wax in quantity of less than20% of the whole, such high melting point waxes being hydrogenatedvegetable oil wax, montan wax, halo-wax, candelilla, wax, and mineralbeeswax or ceresin waxesfcontaining carnauba wax. Thus mineral beeswax'or ceresin wax containing carnauba or other high melting point wax canbe mixed with latex and petroleum wax paraffin or a plastic wax to raisethe exudation and dry meltingv points forv extreme conditions oftemperature and pressure.

The amount of rubber to be included will vary depending upon the filmforming characteristics of the resin and its miscibility with the wax.With polyvinyl acetalv resin which readily forms nlms, as little as .5%of rubber can be included and the rubber may increase as high as from 5to 10%, depending upon the nature of the film desired. With none of! theresins mentioned has it been found desirable to use greater'than 30%rubber. v

Asuitableresin-wax product for liningV and coating containers and partsthereofwill comprise va polyvinyl acetal resin base in amount of atleast substantially 50% and wax in `amount not, greater than 50%. Asexplained above, to such a composition rubber may be included ifdesired, and in amount of at least .5% and less than 30% orV the amount'of rubber may be varied to the end that all of the compositions preparedin accordance with this invention are free of peeling and cracking andhave a melting point above the pasteurization temperature ofsubstantially F.

the resin. Such a film, naturally, possesses greater water resistanceand, at the same time, its strength and iiexibility are not weakenedbecause of the effect of the rubber.

Using 95 parts of the saine latex-wax material (paraffin wax containingrubber) while practically impossible to add 5 parts of polyvinyl acetalresin through the means of heat and agitation, a mutual solvent, such aschloroform or dioxan, eiects a homogeneous mixture. Sufficient solventshould be used so that concentration of polyvinyl acetal resin is notgreater than When the latex and wax are mixed, as in the Weiss patent,the water is evaporated but the latex salts remain. By milling creperubber until A it is very soft, Wax can be added up to as high as 50%.This product is readily soluble in pure wax and, accordingly, a waxcontaining any desired percentage of rubber can be easily and quicklyprepared. Such a rubber-wax product does not contain any of the latexsalts and is readily soluble in many of the polyvinyl acetal resinsolvents. 'I'his is a preferred way of preparing rubber-wax mixtures. y

Urea resins are normally hard and brittle after being insolubilized andthe addition of latexwax is highly desirable in order to increase thestrength and flexibility. Polyvinyl acetal resins are very strong andfiexible but the addition of the rubber-wax compound greatly improvesmoisture resistance. It is preferred to employ a mutual solvent in orderto bring about the best results.

In the accompanying drawing I have shown and facing materials inaccordance with this invention. It is to be understood that theinvention is applicable to containers generally, as well as to caps ofvarious kinds, and is useful with a wide variety of spotting or facingmaterials.

Referring to the drawing:

Figure 1 is a perspective view of a seamless container body.

Figure 2 is a fragmentary sectional view of the same taken through thebody Wall and the seaming ange at the bottom thereof.

Figure 3 is a fragmentary sectional view showing the manner in whichcontainers formed in accordance with this invention are sealed bycoating materials applied to their respective seaming fianges of thebottom and body.

Figure 4 is a sectional view of a cap having a continuous internalcoating on the cushion liner, exposed interior wall of the skirt and theraw edge thereof.

Figure 5 is a sectional view, fragmentary in nature, of strip facingmaterial prepared in accordance with this invention.

Figure 6 is an inside plan view of a closure having a center spot of thematerial of Figure 5.'

Figure 7 is a sectional view of a closure having an overall facing ofthe material shown in Figure 5, and

Figure 8 is a fragmentary sectional view showing a side seam sealed inaccordance with this invention by means of the coating formed on theseaming flanges of the body.

Referring to Figure 1, I have shown a container body I0 of metal whichis drawn from a single blank and includes a top, neck and cap receivingfinish at one end, while at the other end the seamless body is providedwith a laterally extending seaming ange II. This seam- V for puiposes ofillustration containers, closures,

less container body is formed in accordance with application Serial No.334,876.

In Figure 2, I have shown the interior of the body Wall III providedwith a base coating I2 and a surface coating I3 being one of thecompositions above set forth It will be noted that the surface coatingI3 is continuous and coats the surface of the sealing ange II.

In Figure 3, I have shown a container, such as illustrated in Figure 1,sealed with a bottom indicated as a whole at I4. This bottom is coatedon its interior surface in the same manner as described in connectionwith Figure 2, namely, with a base coat I2, and a surface coat I3. Itwill be noted that the seaming iiange Il of the body and the seamingflange I5 of the bottom are provided with iilins continuous with the lmI3, and when the body and bottom are united together into a seam asshown in Figure 3, these coatings provide a very satisfactory seal.

Referring to Figure 8, I have illustrated a container having a side seamI6, the wall Il) of the container body being provided with a basecoating I2 and a surface coating I3 in accordance with this invention.The seaming flanges I1 are similarly coated and the coating iscontinuous with the coating on the wall of the body III. In this manner,when the anges I'I are, seamed together, the resultant side seam issuitably sealed by the coating. In this connection, the side seam canwill have its bottom seamed thereto in the manner shown in Figure 3 andsealed in the saine way, and this will likewise be true in the case ofthe top for the container, the top and bottom being usually referred toas ends Referring to Figure 4 there is illustrated a crown cap having askirt 20, a cushion liner 2|, and a film 22 in accordance with thepresent invention continuously coating the cushion liner, the adiacentexposed inner wall of the skirt, and the free edge thereof.

In Figure 5, I have shown a spotting material of paper in which 25indicates the paper backing layer, 26 the adhesive layer, 21 the basecoat, and 28 a surface coating in accordance with the present invention.

In Figure 6, I have shown a crown cap having a center spot 29 of thefacing material shown in Figure 5, the spot 29 being adhesively unitedby the adhesive film 26 to a cushion liner of composition cork similarto that shown at 2| in Figure 4.

In Figure 7, I have shown a cap provided with an overall facingindicated as a whole at 30 of the facing material illustrated in Figure5.

As heretofore explained, the lm composed entirely, mainly or includingpolyvinyl acetal resin and other materials provides an excellent seamseal, since it is iiexible and under pressure, for instance, incident tothe seaming operation illustrated in Figures 3 and 8, softenssufficiently to exert the required plastic sealing quality. The sealingmaterial may be upon one seaming iiange or the other, or both thereof inthe constructions shown in Figures 3 and 8. Preferably, the coating on aseaming fiange is continuous with the lining coating on the containerbody, bottom or top.

Referring further to Figure 3, I have shown an external coating for thebody which includes a suitable base layer 3| and a surface coating inaccordance with this invention indicated at 32. A similar exteriorcoating may be applied to the body IU of the side seam container shownin -Figure 8, so that the containers,whether seamless or lfabricated,will have both internal and external coatings prepared in accordance`with the -aforesaid examples. y

Also, in connection with Figure 3, I have shown the bottom I4 providedwith an external coating 33 of tin plate, but such coating may besimilar to the internal coatings, in that it comprises a base coatingand a surface coating as described.

Referring to Figure 5, the backing layer 25 instead of being of papermay be of other cellulosic materials or synthetic materials or metalfoil,such as aluminum, and is usually supplied as a continuous strip foruse in high speed spot applying or facing applying machinery.

While I have illustrated the coatings as in- -cluding a-base coating anda surface coating, it is to 'be understood that the coatings described'herein above may be applied directly to the metal surface, e. g., ofblack iron, without the necessity for an intermediate base coating. E1-Referring to Figures 4, 6 and 'l the caps therein illustrated arecrown caps, but the invention is equally -useful in connection withscrew caps, lug caps, pressed on caps, and, in fact, closures of allcharacters, as well as can ends of various types. In this connectiomtheclosure or can ends may have directly applied to the internal andexternal surfaces thereof coatings in accordance with this invention,namely, apolyvinyl acetal resin coating applied directly to the metal orto an intermediate-base coat. In the case of caps which include acushion liner, this coating may be applied before the cushion liner isassembled in the cap.

In the various examples mentioned above, I have indicated the use ofWax, a plasticizer, or beth. It is to be understood that for somepurposes the Wax and plasticizer may be omitted, or leither one or theother employed. In connection with Example 5, a suitable chemical ordrying oil plasticizer may be used in about the propor- -tions indicatedinthe other examples. In re -ferring to a container part, I intend tocover not only a container body, but a container closure and othercontainer parts referred to herein such as closure facings, can ends,seams', etc.

This application is a continuation-in-part of 'my applications, SerialNo. 78,047, filed May 5, '1936, and Serial No. 350,810, filed August 3,1940.

I claim:

1. A metal container for foods and beverages or part thereof having acoating comprising a base selected from a'group consisting ofwaxes:and-resins and mixtures thereof, and rubber, the rubber being presentin an amount of at least .5% andless than 30% and said coating beingAfree of Apeeling and cracking and having 'a melti'ng 'point 'above thepasteurization temperature of substantially 150 F.

-2. A metal container or part thereof in accordance'with claim 1 inwhich the wax is one 'selected from a; group consisting of paraffin,lozoifzerite, petroleum wax, hydrogenated vegel'table oil wax, montanwax, halo-wax, candelilla, mineral beeswax, ceresin, carnauba andmixtures thereof.

3. A metal container or part'rthereof in accord- 5. A metal container orpart thereof inaccordance with claim 4 in which the base is selectedfrom a group consisting of urea alde'hyde resin. cumar resin andarochlor resin.

6. A metal container or part thereof in accordance with claim 1 in whichthe resin is polyvinyl acetal resin and the wax is present'in greateramount than the resin. i

7. A metal container'or part thereof in accord- -ance with claim 1 inwhich the resin is polyvinyl acetal resin and is present in amount notgreater than 10%, the major portion of the remainder 'of the coatingbeing Wax.

8. A metal container for foods and beverages or part thereof having acoating comprising a resin base of the polyvinyl acetal type, rubber andwax in amount not greater than 50%, said coating being free of 'peelingand cracking and having a melting point above the pasteurization temperature of substantially F.

9. A metal container for foods and beverages or part thereof having acoating comprising a resin base of the polyvinyl acetal type,chlorinated rubber and wax in -amount not greater than 50%, said coatingbeing'free of peeling and cracking and having a melting point above thepasteurization temperature of substantially 150 10. A metal containerfor foods and beverages or part thereof having a coating comprising aresin base in amount of at least 50%, said resin base comprisingpolyvinyl-acetal resin, and rubber, said coating being free of peelingand cracking and having a melting point above pasteurizationtemperature.

11. A metal container for foods and beverages or part thereof having acoating comprising a resin base of the polyvinyl acetal type and Wax in`and having a melting point above the pasteurization temperature ofsubstantially 150 F.

13. A metal container for foods and beverages or part thereof having acoating comprising a resin base in amount of at least 50%, said resinbase comprising polyvinyl acetal resin and an alkyd resin, and rubber,said coating being free of peeling and cracking and having a meltingpoint above pasteurization temperature.

CHARLES E. MCM'ANUS.

